Analysis of Asymmetrical Modes in Medium Voltage Electrical Grids with Compensated Neutral

Abstract

Abstract. A mathematical model of steady-state radial medium voltage electrical network with earthed neutral via arc-suppression coils has been carried out. A detailed equivalent circuit of the examined network using the completed equivalent circuit of phase coordinates methods and Kirchhoff's laws has been developed. The system of mathematical models equations has been completed. The advantage of the created mathematical model is the ability to increase the accuracy of the simulation by a detailed account of features of a network with arc-suppression coils. The mathematical model considers the load currents, the non-linear nature of consumers, the impact of the power lines asymmetry. Using the developed mathematical model there are presented results of the carried out researches of three power lines with different cross sections with neutral grounding via arc-suppression coils. The analysis of asymmetry parameters impact of power lines on the value of the neutral displacement voltage and on the voltage value at the end of the lines at different values of the reactor inductance has been completed. The conclusion about the model possibility to perform validation of the reactor tuning, to evaluate voltage quality parameters, to carry out the formation of reliable initial conditions for calculating the overload in the single-phase earth faults. In conclusion the model performs validation of the reactor tuning and it evaluates voltage quality parameters in order to carry out the formation of reliable initial conditions. It also calculates the overload in the single-phase earth faults.

The Power Quality Improving and its Losses Reducing with Balancing Devices

“…Numerous publications on the considered networks operating modes study are devoted to their functioning consideration in low power quality conditions [1][2][3][4][5][6][7][8]. Many years research in this area have allowed to establish that the most characteristic and objective 0.38 kV networks operation modes is the asymmetric mode (AM) [9][10][11][12][13][14]. On the one hand, these modes lead to an increase in unproductive electricity losses, including the fire hazardous situations possibility [15][16], on the other hand, to a significant decrease in the electricity quality characteristics, which leads to inadequate electric receivers operation.…”

The 0.38 kV “Green Network” Operating Modes Simulation with Multi-Level Unbalanced Power Consumption

“…This is due to the such networks saturation with new transformation means (for example, photovoltaic plants), as well as intelligent means that allow modes automatic control without human intervention (for example, flows that degrade the power quality). A publications significant number are devoted to the electrical networks various models creation and their operating modes analysis [1][2][3][4][5][6][7][8][9].…”

About Electric Energy Additional Losses Reduction at the Phase Currents Unbalancing in the 0.38 kV Operating Networks

“…At the same time, the calculation methods approbation and programs created on the mathematical modeling basis, directly for the analysis electrical netw orks operating modes existing, is considerable interest. Numerous studies devoted to the operating modes modeling [1][2][3][4][5][6][7], as well as studies related to the electrical energy parameters measurement and calculation in operating 0.38 kV electrical networks [8][9][10][11][12][13][14] show that these networks operating modes are objectively…”